1. Field of the Invention
The present invention relates to a cap that covers an electric wire connecting portion in which respective conductive portions of a plurality of electric wires are interconnected, and relates to a manufacturing method of the cap.
2. Description of the Related Art
For example, in cabling of a wire harness, insulating outer sheaths of a plurality of electric wires are stripped, and exposed conductive portions are interconnected, whereby an electric wire connecting portion is formed. Moreover, a cap made of an insulating material is used in order to ensure insulating property, waterproof and the like of a spot of the electric wire connecting portion.
As this type of the conventional cap, one shown in FIGS. 1A and 1B and one shown in FIGS. 2A and 2B are disclosed in Japanese Patent Laid-Open Publication No. H11-178142 (published-in 1999). The cap 100 shown in FIGS. 1A and 1B is one formed by injection molding using a metal mold. The cap 100 is composed of: a cylinder 101 in which one end is closed; and a tongue portion 102 protruded from the other end of the cylinder 101.
In work to cover an electric wire connecting portion 105 of a plurality of electric wires W by using the cap 100, first, as shown in FIG. 1A, the electric wire connecting portion 105 of the plurality of wires W is inserted into the cylinder 101 of the cap 100. Next, as shown in FIG. 1B, the tongue portion 102 of the cap 100 is bound with the plurality of electric wires W by a tape 106, and this is the end of the work.
The cap 110 shown in FIGS. 2A and 2B is composed of: a heat-shrinkable tube 111 formed by extrusion molding, in which both ends are opened; and a hot melt layer 112 adhered onto an inner surface of the heat-shrinkable tube 111.
In work to cover the electric wire connecting portion 105 of the plurality of wires W by using the cap 100, first, as shown in FIG. 2A, the electric wire connecting portion 105 of the plurality of electric wires W is inserted into the heat-shrinkable tube 111. Next, as shown in FIG. 2B, the cap 110 is heated by a hot wind and the like. Then, the heat-shrinkable tube 111 shrinks by being heated, and in addition, the hot melt layer 112 is solidified by a temperature drop caused after such heating, and this is the end of the work.